package org.smart4j.framework.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileFilter;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * 类加载搜索工具类
 * Created by chinalin on 2017/3/15.
 */
public final class ClassUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(ClassUtil.class) ;

    /**
     * 获取类加载器
     */
    public static ClassLoader getClassLoader(){
        //TODO
        return  Thread.currentThread().getContextClassLoader() ;
    }

    /**
     *加载类
     * isInitialized默认 true ，执行加载类的静态代码块
     */
    public static Class<?> loadClass(String className){
        return loadClass(className , true) ;
    }

    /**
     *加载类
     * isInitialized是否初始化标志，是指是否执行加载类的静态代码块,设为false可以提高加载类性能。
     */
    public static Class<?> loadClass(String className, boolean isInitialized){
        Class<?> cls ;
        try{
            cls = Class.forName(className, isInitialized, getClassLoader());
        } catch (ClassNotFoundException e){
            LOGGER.error("load class failure" ,e );
            throw new RuntimeException(e) ;
        }
        return cls ;
    }

    /**
     * 获取指定包名下的所有类
     */
    public static Set<Class<?>> getClassSet(String packageName){
        packageName = packageName.trim() ;  //去掉前后空格
        Set<Class<?>> classSet = new HashSet<Class<?>>() ;
        try {
            Enumeration<URL> urls = getClassLoader().getResources(packageName.replace(".", "/")) ;
            while (urls.hasMoreElements()){
                URL url = urls.nextElement() ;
                if (url != null){
                    String protocol = url.getProtocol() ;   //获取协议
                    if (protocol.equals("file")){
                        String packagePath = url.getPath().replaceAll("%20","");
                        addClass(classSet, packagePath, packageName) ;
                    } else if (protocol.equals("jar")){
                        JarURLConnection jarURLConnection = (JarURLConnection) url.openConnection();
                        if (jarURLConnection != null){
                            JarFile jarFile = jarURLConnection.getJarFile() ;
                            if (jarFile != null){
                                Enumeration<JarEntry>   jarEntries = jarFile.entries() ;
                                while (jarEntries.hasMoreElements()){
                                    JarEntry jarEntry = jarEntries.nextElement() ;
                                    String jarEntryName = jarEntry.getName() ;
                                    if (jarEntryName.endsWith(".class")){
                                        String className = jarEntryName.substring(0,jarEntryName.lastIndexOf(".")).replaceAll(("/"), ".") ;
                                        doAddClass(classSet, className) ;
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }catch (Exception e){
            LOGGER.error("get class set failure", e);
            throw new RuntimeException(e) ;
        }
        return classSet ;
    }

    private static void addClass(Set<Class<?>> classSet, String packagePath, String packageName){
        File[] files = new File(packagePath).listFiles(new FileFilter() {
            public boolean accept(File file) {
                return ((file.isFile() && file.getName().endsWith(".class")) || file.isDirectory());
            }
        });
        for (File file : files){
            String fileName = file.getName() ;
            if (file.isFile()){
                String className = fileName.substring(0, fileName.lastIndexOf("."));
                if (StringUtil.isNotEmpty(packageName)){
                    className = packageName + "." + className ;
                }
                doAddClass(classSet, className) ;
            } else {
                String subPackagePath = fileName ;
                if (StringUtil.isNotEmpty(packagePath)){
                    subPackagePath = packagePath + "/" + subPackagePath ;
                }
                String subPackageName = fileName ;
                if (StringUtil.isNotEmpty(packageName)){
                    subPackageName = packageName + "." + subPackageName ;
                }
                addClass(classSet, subPackagePath, subPackageName);
            }
        }
    }
    private static void doAddClass(Set<Class<?>> classSet , String  className){
        Class<?> cls = loadClass(className, false);
        classSet.add(cls) ;
    }
}
